To date, pharmacological treatment options for progressive supranuclear palsy (PSP), a neurodegenerative tauopathy, are limited. The MAO-B inhibitor rasagiline has shown neuroprotective effects in preclinical models of neurodegeneration. To evaluate the safety, tolerability and therapeutic effect of rasagiline on symptom progression in PSP. In this 1-year randomized, double-blind, placebo-controlled trial, 44 patients fulfilling the NINDS-PSP criteria were randomized to 1 mg/d rasagiline or placebo. The combined primary endpoint included symptom progression as measured by the PSP rating scale (PSP-RS) and the requirement of L-dopa rescue medication. Secondary endpoints included Schwab and England Activities of Daily Living (SEADL), Montgomery-Åsberg Depression Rating Scale, Mini Mental State Examination, Frontal Assessment Battery and posturographic measurements. Of the 44 patients randomized, 26 completed the trial per protocol. Rasagiline was well tolerated, with a slight increase of known side effects (hallucinations, ventricular extrasystoles). No effect on the primary endpoint (p = 0.496) was detected. Symptom progression averaged at 11.2 (rasagiline) and 10.8 (placebo) points per year (ΔPSP-RS). No difference was seen in SEADL, depression, cognitive function, frontal executive function and posturographic measurements. Post hoc analyses of PSP-RS subdomains indicate a potential beneficial effect in the "limb motor" subdomain, whereas performance appeared lower in the "mentation" and "history" subdomains in the treatment group. While rasagiline is well tolerated in PSP, a beneficial effect on overall symptom progression was not detected. Post hoc analyses suggest the implementation of more specific endpoints in future studies.
Keywords: Clinical trial; Progressive supranuclear palsy; Rasagiline; Tauopathy.